In the Talmud Nedarim 65a, Chazal teach that Yisro made Moshe Rabbeinu swear to him that he would never leave without permission. The Yalkut has a different perspective on Yisro’s requirements for Moshe to fulfill before he would agree to give him his daughter in marriage. Moshe asked for Tziporah. Yisro agreed, on the condition that Moshe promise to carry out the one request that Yisro had of him. Moshe agreed. Yisro presented what is considered to be atypical of him. On the other hand, it is also frightening that Moshe would accede to the request. He said, “The first son produced by your marriage must be handed over to avodah zarah, idol-worship. After that, the rest can be dedicated to Heaven Above. The first one, however, is mine.” Moshe agreed. The source of this Chazal is the Mechilta to Parashas Yisro. Targum Yonasan supports this Midrash, since he writes that Moshe had not performed a Bris Milah, circumcision, on Gershom, as he did for Eliezer, since Yisro had forbidden it. Gershom belonged to the Pagans. How did Yisro make such an impossible demand, and why did Moshe agree to it? This Midrash is laden with difficulty.
Horav Zevulun Charlop, zl, illuminates this Midrash for us with a practical explanation. First, why would Yisro make such a foolish demand? He had personally mastered every religion, and acknowledged the folly of each one of them. It is, therefore, ludicrous to think that Yisro would demand that his first grandson be given to the pagans. He clearly knew better. Therefore, we must submit that, in effect, it was just the opposite. Yisro was not attempting to destroy his grandson; he was actually making an intelligent attempt to save him.
Yisro was acutely aware of the worthless validity of pagan worship. He had been there and done that. Idol worship was a sham. It was one large vacuum, but people had a tremendous gravitational pull to idol worship. How was he to spare his grandsons and future descendants from falling prey to this immoral hypocrisy of religion? When Yisro met Moshe, his concern was raised. After all, the “Egyptian” man was the product of a country whose very foundation was firmly entrenched in idol worship. Therefore, Yisro had serious reservations concerning allowing his daughter to marry Moshe, unless he would accede to Yisro’s request that not all of his children be permitted to worship idols. Thus, when Yisro said, “The ‘first one’ and afterwards the ‘rest are to belong to Heaven Above,’” the critical and most important part of Yisro’s request was concerning the rest of the children. Yisro knew that he would probably have to give in on the first son, but, afterwards, they would all belong to Hashem.
Why did Yisro not demand that the first one also belong to Hashem? He feared the backlash from the other Midyanite priests who were not very pleased with his monotheistic leanings. If he would make too many “unrealistic” demands, they might kill him, his daughter and Moshe. By giving up one son, he made himself appear supportive of the Midyanite pagan culture. Over time, they would work things out.
What would be the test to affirm Moshe’s acquiescence to Yisro’s demand? Bris Milah. If Moshe did not circumcise his firstborn, it would be an indication that he was dedicating his first son to the pagan culture. Moshe, fearing for his life and the lives of the members of his family, delayed the Bris Milah until a more opportune venue. This is why he was not punished for his laxity in carrying out the mitzvah. When he left Midyan and was at the inn, the angel came to carry out the punishment. Since he was now beyond the tentacles of the Midyanite priests, the dispensation of pikuach nefesh, life endangerment, was no longer in effect.
